[TriEmbed] Substitute transistor

Carl Nobile carl.nobile at gmail.com
Sat Dec 18 14:34:36 CST 2021


Paul,

Can you track down what is feeding the display its power? There may be
something kaflooey in the PS. No doubt another cap, but check the PS out or
something between the PS and the display.

~Carl


On Sat, Dec 18, 2021 at 3:02 PM The MacDougals via TriEmbed <
triembed at triembed.org> wrote:

> I replaced the transistor with an exact match from ebay and a couple of
> electrolytic caps (at Carl’s suggestion).
>
> The display is still dim.  Oh well.
>
>
>
> ---> Paul
>
>
>
>
>
> *From:* TriEmbed <triembed-bounces at triembed.org> *On Behalf Of *The
> MacDougals via TriEmbed
> *Sent:* Friday, November 26, 2021 9:11 PM
> *To:* triembed at triembed.org
> *Subject:* [TriEmbed] Substitute transistor
>
>
>
> My microwave display suddenly went very dim.  I opened it up and found a
> discolored
>
> spot on a circuit board feeding the display (see attached image).  That
> component is
>
> marked B1238, so I assume it is a 2SB1238, which is obsolete.
>
>
>
>
> https://www.digikey.com/en/products/base-product/rohm-semiconductor/846/2SB1238/30307
>
> Medium power transistor( 80V, 0.7A) 2SB1189 / 2SB1238 Features 1) High
> breakdown voltage, BVCEO= 80V, and high current, IC= 0.7A.
>
> 2) Complements the 2SD1767 / 2SD1859. Absolute maximum ratings (Ta=25C)
> Parameter Symbol Limits Collector-base voltage VCBO −80 Collector-emitter
> voltage VCEO −80 Emitter-base voltage VEB O −5 Collector current IC −0.7 C.
>
>
>
> Anyone want to help me find a replacement?
>
> I dug through my Dad’s stash of old electronics and found a TIP30B, which
> looks like it might work.
>
>
>
>
>
> ---> Paul
>
>
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-- 
--------------------------------------------------------------
Carl J. Nobile (Software Engineer/API Design)
carl.nobile at gmail.com
--------------------------------------------------------------
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